November 2025 OBS Discussion

[psv88]

So much for that mostly sunny forecast!

[SACRUS]

22 minutes ago, psv88 said:

So much for that mostly sunny forecast!

 

Yeah clouds again hanging on and pushing in

 

[Dark Star]

18 hours ago, Wannabehippie said:

Keep in mind that chatGTP is not the be all and end all of accuracy. it is only as good as the search terms, and what is inputted in to it. Too many variables at this point with it IMHO.

 

I assume that future AI models will be excellent, being able to correct biases, and errors from the last run if initial 6 hour forecast(s) don't verify.  Anyways, I'm optimistic (for once)...

[Dark Star]

17 hours ago, Sundog said:

Do you know how hard it is for the EPS to show such a negative anomaly in the long range with our background state?

Not sure.  Stratospheric warming is supposed to bring down colder air, although I'm not sure this exact scenario as pictured will materialize...

[anthonymm]

6 hours ago, Sundog said:

I mean if all it takes is a cold Siberia and warm Pacific to end winter then we are never going to get cold and snow ever again

This but unironically. The pac jet permanently cancelled snow odds for the tristate.

[MJO812]

27 minutes ago, anthonymm said:

This but unironically. The pac jet permanently cancelled snow odds for the tristate.

We need it to cooperate.  It is a bigger factor than the nao imo.

[donsutherland1]

A generally milder than normal pattern will likely continue through next Wednesday when a system could bring a period of rain. However, exceptional warmth appears unlikely. 

The closing days of November will likely turn colder. There is potential for New York City's Central Park to experience its first freeze of 2025. The 1991-2020 normal first data is November 21. The 1961-1990 baseline was November 11. Last winter's first freeze occurred on November 30.

The opening days of December will turn milder. However, colder conditions could begin to develop during the second half of that week and continue through the second week of December. Severe cold appears unlikely through at least the first 10 days of December. Afterward, the pattern evolution will depend, in part, on how the imminent stratospheric warming event propagates. 

Meanwhile, today will be Central Park's 1,394th consecutive day without daily snowfall of 4" or more. That ties the record of 1,394 days was set during February 22, 1929 through December 16, 1932. That stretch ended with 6.7" daily snowfall on December 17, 1932.

The ENSO Region 1+2 anomaly was -0.7°C and the Region 3.4 anomaly was -0.7°C for the week centered around November 12. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.16°C and the ENSO Region 3.4 anomaly has averaged -0.65°C. La Niña conditions will likely continue through at least mid-winter.

The SOI was +38.17 today. 

The preliminary Arctic Oscillation (AO) was +0.805 today. 

Based on sensitivity analysis applied to the latest guidance, there is an implied 85% probability that New York City will have a cooler than normal November (1991-2020 normal). November will likely finish with a mean temperature near 46.7° (1.3° below normal). 

Supplemental Information: The projected mean would be 1.0° below the 1981-2010 normal monthly value. 

[Dark Star]

1 hour ago, MJO812 said:

We need it to cooperate.  It is a bigger factor than the nao imo.

Pacific Jet has been a relentless monster for the NYC metro area for years.  

[eduggs]

At 12z the CMC and GFS were in decent agreement all the way out to day 7. Now at 0z they suddenly diverge pretty significantly as early as day 5. They've kind of switched places with the GFS suddenly much deeper and further southwest with a mature ULL meandering through CA and the CMC moving away from that look towards a more positively tilted and further east trof.

The take home message is that this is a period of high model volatility. It probably doesn't matter much because either way we're too far from the cold air (through the mid-range) until the moisture is gone. I prefer the CMC look, however. It keeps us a little closer to the goods. I despise the deep ULLs burying themselves in CA , which are really hurting our chances.

[eduggs]

I haven't looked at the UKMET in a while. The 0z is also significantly divergent from the (hideous) GFS as early as day 5 and pretty cold at the end of its 7 day run. It actually tries to get some snow into our area on Sunday with the weak in-between shortwave. Other guidance has this feature very weak or further north. I'm happy with any model run that doesn't send repeated cutoffs to CA.

I'd love to see the ECM and EC-AI move away from the southwest cutoff at 0z.

[donsutherland1]

Today will be New York City's (Central Park) 1,395th consecutive day without a 4" (10.2 cm) or above daily snowfall. That will break the record of 1,394 days that was set during February 22, 1929 through December 16, 1932.

[The 4 Seasons]

39 minutes ago, donsutherland1 said:

Today will be New York City's (Central Park) 1,395th consecutive day without a 4" (10.2 cm) or above daily snowfall. That will break the record of 1,394 days that was set during February 22, 1929 through December 16, 1932.

where did you get this data? and can you sort by other snowfall amounts, like 3" or 6" or 10"?

[donsutherland1]

10 minutes ago, The 4 Seasons said:

where did you get this data? and can you sort by other snowfall amounts, like 3" or 6" or 10"?

From xmACIS. We're years away from the 3" record (289 days vs. record of 1,110 days); 6" record (1,395 days vs. record of 2,572 days); and, 10" record (1,757 days vs. record of 3,266 days).

https://xmacis.rcc-acis.org/

[The 4 Seasons]

6 minutes ago, donsutherland1 said:

From xmACIS. We're years away from the 3" record (289 days vs. record of 1,110 days); 6" record (1,395 days vs. record of 2,572 days); and, 10" record (1,757 days vs. record of 3,266 days).

https://xmacis.rcc-acis.org/

oh, wow thanks. This site is almost identical to cornells climodv2 that i've been using for snowfall amounts for maps since it pulls from coop,cocorahs and climo sites but this is even nicer and it tells you what the source is! thats awesome, i think ill switch to this one. 

[wdrag]

IF wind advisory Fri, think it will be mostly  5A-Noon.  No thread on this til at least Wed...too marginal. 

[Sundog]

1 minute ago, wdrag said:

IF wind advisory Fri, think it will be mostly  5A-Noon.  No thread on this til at least Wed...too marginal. 

As long as Thanksgiving is good so that the balloons can fly high.